Short-term impacts of solar lanterns on child health : experimental evidence from Bangladesh

We implemented a 16-month randomized field experiment in unelectrified areas of Bangladesh to identify health impacts of solar lanterns among school-aged children. Our analysis of various health-related indicators?self-reporting, spirometers, and professional medical checkups?showed modest improvements in eye redness and irritation but no noticeable improvement in respiratory symptoms among treated students. Varying the number of solar products received within treatment households did not alter these results. This limited health benefit was not caused by nonutilization of the products by treated children, spillover effects from treated to control students, or treatment heterogeneity resulting from unfavorable family cooking environments

Impacts of solar lanterns in geographically challenged locations : experimental evidence from Bangladesh

Despite continuous efforts to improve the coverage, the access to electricity remains insufficient in many developing countries, particularly in geographically challenged locations, due mostly to the high cost of grid extension. To rigorously investigate the effectiveness of solar products as an alternative in remote areas, we conducted a randomized controlled trial in river islands of northern Bangladesh where no grid-based electricity is available. We found that solar lanterns significantly increased home study hours among schooled children, especially in the night and before exams. School attendance rate also initially increases due to the provision of solar lamps, although such effects fade away over time. The increased study time and initial school attendance rate, however, did not improve children\u27s exam results. We also found marginal improvements on health-related indicators, such as eye redness and irritation, but negligible impacts on respiratory indicators. Households that received solar lanterns substituted the traditional lighting sources with modern technology, leading to a significant decrease in annual biomass fuel consumptions, particularly kerosene. Finally, treated households showed a greater self-reported willingness to purchase solar products compared with the control group

One-loop unitarity of scalar field theories on Poincare invariant commutative nonassociative spacetimes

We study scalar field theories on Poincare invariant commutative nonassociative spacetimes. We compute the one-loop self-energy diagrams in the ordinary path integral quantization scheme with Feynman's prescription, and find that the Cutkosky rule is satisfied. This property is in contrast with that of noncommutative field theory, since it is known that noncommutative field theory with space/time noncommutativity violates unitarity in the above standard scheme, and the quantization procedure will necessarily become complicated to obtain a sensible Poincare invariant noncommutative field theory. We point out a peculiar feature of the non-locality in our nonassociative field theories, which may explain the property of the unitarity distinct from noncommutative field theories. Thus commutative nonassociative field theories seem to contain physically interesting field theories on deformed spacetimes.Comment: 25 pages, 9 figures ; appendix and references adde

Transport coefficients of D1-D5-P system and the membrane paradigm

I discuss a correspondence between string theory and the black hole membrane paradigm in the context of the D1-D5-P system. By using the Kubo formula, I calculate transport coefficients of the effective string model induced by two kinds of minimal scalars. Then, I show that these transport coefficients exactly agree with the corresponding membrane transport coefficients of a five-dimensional near-extremal black hole with three charges.Comment: 11 pages, no figure; v2: minor corrections, accepted for publication in Physical Review

Effects of Orthogonal Rotating Electric Fields on Electrospinning Process

Electrospinning is a nanotechnology process whereby an external electric field is used to accelerate and stretch a charged polymer jet, so as to produce fibers with nanoscale diameters. In quest of a further reduction in the cross section of electrified jets hence of a better control on the morphology of the resulting electrospun fibers, we explore the effects of an external rotating electric field orthogonal to the jet direction. Through extensive particle simulations, it is shown that by a proper tuning of the electric field amplitude and frequency, a reduction of up to a $30 \%$ in the aforementioned radius can be obtained, thereby opening new perspectives in the design of future ultra-thin electrospun fibres. Applications can be envisaged in the fields of nanophotonic components as well as for designing new and improved filtration materials.Comment: 22 pages, 8 figure